On your subsequent clarification I shall render my further opinion:
1. property was purchased by 3 brothers jointly and occupied. 1st brother's title is now in the hands of his widow and 2 children.
Therefore the property belongs absolutely to the 3 brothers alone and upon anyone's death, there respective share in the property shall devolve on their respective legal heirs.
2. 2nd brother died unmarried i.e. without any wife or children
His share of property shall devolve on his surviving class II legal heirs (in the absence of class I legal heirs) The list of Class II legal heirs is given below:
II (1) Son's daughter's son, (2) son's daughter's daughter,(3) brother, (4) sister.
III (1) Daughter's son's son (2) daughter's son's daughter, (3) daughter's daughter's son (4) daughter's daughter's daughter.
IV. (1) Brother's son (2) sister's son, (3) brother's daughter, (4) sister's daughter.
V. Father's father; father's mother.
VI. Father's widow; brother's widow.
VII. Father's brother; fathers' sister.
VIII. Mother's father; mother's mother.
IX. Mother's brother, mother's sister.
3. 3rd has psycho problem and during treatment transferred his title to his wife's name and has mutation certificate in wife's name.
He is the owner of his share in the property, he can very well transfer the property in his wife's name, the question is whether this transfer was made at the time when he was not in sound mind or insane, if so, then this transfer may not be considered as valid if proved with evidence at a later stage.
4. 2 married sister lived other place and never lived here, one of them also died keeping 1 son and husband behind.
Both the sisters actually do not have any right in the property even if they lived in it earlier because it was jointly purchased by their brothers out of their own funds. However, one surviving sister may stake a share in her unmarried deceased brother's share in the property along with her surviving brother.
now the living sister and died sister's heir has any right on this property i.e. died brother's property ?
Read the last line of the above answer.
the living sister and died sister's heir can issue NOC for mutation in my favor and accept cash giving receipt without signing deed of sale and presenting it to the registrar?
The surviving sister of the deceased brother shall become the Class II legal heir along with her surviving brother to stake claim in her unmarried deceased brother's share in the property. Hence she along with her brother have to jointly execute the registered sale deed in favor of the buyer or they can both execute a registered gift deed in respect of their share in the property in favor of the other shareholder/owner who is negotiating the sale a a vendor with the buyer, then the proposed vendor shall hold the marketable title to sell the properties intended to be sold.
can the land office allow a mutation in my favor for the part of 1st brother full and a fraction of 2nd brother for which 1st and 3rd brother will sign - if sisters refuse to sign?
The mutation process will appear only after you have purchased the property, so first purchase the property properly and legally by taking a proper legal opinion from an expertise lawyer in the local and then look for the formalities of mutation of revenue records.